Extruded golf club head and method of manufacture

ABSTRACT

A golf club head is machined from an extruded bar having an irregular cross-section that is near-net-shape to the vertical profile of the club. To form the club head, the extruded bar is sliced into a club head blank. The blank is secured to a machining fixture and machined into the final configuration. Because the club head blanks are formed from an extrusion that is already near-net-shape to the profile of the club, less metal is removed during the machining operations, which results in faster process times, less wasted material and therefore substantial cost savings over the prior art methods of manufacturing golf club heads.

BACKGROUND OF THE INVENTION

The present invention relates to golf club heads and in particular to golf putters and irons.

Golf club putters and irons are traditionally made by an investment casting procedure sometimes referred to as lost-wax casting. According to this method, a wax replica of the club head is made by pouring wax into a mold. The wax replica is then dipped repeatedly into a ceramic slurry to build-up a ceramic mold of sufficient thickness to withstand the metal molding process. The wax is melted out of the mold and then the ceramic is fired to harden it. After it has been fired, the ceramic mold is filled with molten metal. Once the metal has cooled, the mold is broken off to reveal a club head blank that is ready for finish machining, which may include several steps of grinding, polishing, and/or milling.

An alternative method of forming a club head blank is by forging. According to this process, a heated slug of metal is hammered or pressed between a male and female die to form the heated metal into the rough shape of the golf club head. The rough forgine is then subjected to additional machining steps to form the finished club head.

Golf club heads have also traditionally been made by milling the club head out of a solid billet of metal. This, however, is the most expensive way to fabricate a club head because most of the raw material is wasted in the machining process. Typically, the finished club head weighs from 10% to 20% of the original weight of the billet. The remaining 80% to 90% of the billet ends up as chips on the machine room floor.

All of the foregoing methods have their disadvantages. In the lost-wax casting process the build up of the mold takes several days and is labor intensive. Forging is expensive because of the additional tooling and machine operations necessary to forge the blanks and it can only be carried out on materials that respond well to forging. As noted hereinbefore, milling is the most expensive method of manufacturing because of the time necessary to mill a solid billet of metal and because of the substantial wasted material.

SUMMARY OF THE INVENTION

The present invention comprises a method of manufacturing a golf club head in which the club head is machined from an extrusion that is already near-net-shape to a vertical profile of the finished club head. According to one embodiment of the invention, an extruded bar having an irregular cross-section that is near-net-shape to the front profile of the club is sliced into a club head blank. Datum are formed in the club head blank by drilling positioning holes, which are used to secure the club head blank to a machining fixture. The club head blanks are then machined into the final configuration including the face, the rear body and hose1 shank while secured to the fixture. In an alternative embodiment of the present invention, the club head blanks are sliced from an extrusion having an irregular cross-section that is near-net-shape to the side profile of the finished club head. A datum surface is created by rough machining a tab that extends forward from what will be the face of the club. The club head blank is secured to a machining fixture by clamping the tab to the fixture. The club head body is then machined into its finished form, after which the face is machined, removing the tab in the process.

Because the club head blanks are formed from an extrusion that is already near-net-shape to the profile of the club, less metal is removed during the machining operations, which results in faster process times, less wasted material and therefore substantial cost savings over the prior art methods of manufacturing golf club heads.

BRIEF DESCRIPTION OF THE DRAWING

The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawings figures in which like references designate like elements and, in which:

FIG. 1 is a front elevational view of a golf club incorporating features of the present invention;

FIG. 2 is a rear perspective view of the golf club of FIG. 1;

FIG. 3 is a front perspective view of a club head blank used to manufacture the club head of FIG. 1;

FIG. 4 is a perspective view of a plurality of club head blanks mounted on a fixture for machining in accordance with the present invention;

FIG. 5 a is a vertical cross section of the club head blank of FIG. 3;

FIG. 5 b is a representation of the front profile of the golf club of FIG. 1 projected onto a vertical surface parallel to a horizontal line tangent to the face;

FIG. 6 is a perspective view of an alternative embodiment of a club head incorporating features of the present invention;

FIG. 7 is a perspective view of a club head blank used to manufacture the club head of FIG. 6;

FIG. 8 a is a vertical cross section of the club head blank of FIG. 6; and

FIG. 8 b is a representation of the side profile of the golf club head of FIG. 6 projected onto a vertical plane normal to the face.

DETAILED DESCRIPTION

With reference to FIGS. 1 and 2, a golf club head 10, preferably a golf putter head, comprises a body 12 and a hose1 shank 14 with a boss 16 counterbored for receiving one end of a golf club shaft (not shown). The body 12 has a front face 18, a heel end 20 and a toe end 22. Front face 18 may optionally include a face insert 24 secured within a recess in face 18. Golf club head 10 is fully machined from a metal material such as steel, titanium, or preferably an aluminum alloy such as Alcoa C805-T6511 or berrylium-free alloy C37H-T6511.

With reference to FIG. 3, golf club head 10 is machined from a club head blank 26. Club head blank 26 is formed by sawing-off a portion of an extruded bar 28, along a plane 27 transverse to the longitudinal axis 29 of extruded bar 28. As can be seen from FIG. 3, the cross-section of extruded bar 28 defines a surface 30 that is near-net-shape to (i.e., having an area no more than 150% greater than) the area of the vertical front profile of club head 10. After club head blank 26 is severed from extruded bar 28, positioning holes 32 and 34 are drilled through tabs 36 and 38 of club head blank 26. Positioning hole 33 is similarly drilled through hose1 shank portion 37 of club head blank 26. Positioning holes 32, 33 and 34 are then used to secure club head blank 26 to a fixture such as a “tombstone” horizontal milling fixture 40 as shown in FIG. 4. Once attached to tombstone 40, club head blank is machined to form the rear surface of the body and hose1 shank of club head 10. Club head blank 26 is then reversed and attached to tombstone 40 to allow the face and remaining features of golf club head 10 to be machined. Golf club head 10 is then removed from the tombstone 40 to permit tabs 36 and 38 to be removed and the hose1 bore to be drilled into boss 16.

With reference to FIGS. 5 a and 5 b, if the front profile of golf club head 10 is projected onto a vertical plane parallel to a horizontal line tangent to face 18 it yields a profile 40 encompassing an area of approximately 4.9 inches. The area of surface 30 of club head blank 26 is less than 10 square inches and is preferably approximately 8 square inches. Accordingly, throughout the entire machining operation the surface area 30 of club head blank 26 is reduced by only 40%-50%, that is, the area of profile 40 of the finished club head 10 is from 50%-60% of the area of the cross-section of extruded bar 28. This compares very favorably to solid billet machining in which 80%-90% of the billet is machined away.

FIG. 6 is a perspective view of an alternative embodiment of a golf club manufactured according to the present invention. For “mallet” style putters or other clubs that do not have a hose1 shank, such as club head 42, in accordance with the present invention, the least amount of material is wasted if the club head is machined from a club head blank that is near-net-shape to the vertical side profile of the club. Accordingly, club head 42, which comprises a face 44 and a body 46 is formed from a club head blank 50 that is near-net-shape to the side profile of club head 42. With reference to FIG. 7, club head blank 50 itself is formed by severing a portion of an extruded bar 52 along a plane 53 transverse to the longitudinal axis 54 of the extruded bar 52. As can be seen from FIG. 7, the cross section of extruded bar 52 is near-net-shape to the vertical side profile of club head 42.

To form club head 42, club head blank 50 is attached to a machining fixture similar to tombstone 40 by clamping tab 56 to the machining fixture. Once club head blank 50 is clamped in place, the lateral surface 58, lower surface 60 and upper surface 62 of body 46 are machined. Thereafter, club head blank 50 is removed from the machining fixture and placed in a second fixture to allow tab 56 to be machined off and face 44 finished. Thereafter, hose1 bore 48 is drilled into body 46 to complete the club head.

With reference to FIG.s 8 a and 8 b, the side profile of club head 42 projected onto a vertical plane normal to face 44 generates a contour 64 encompassing an area of approximately 1.56 square inches. The cross-sectional area 66 of extruded bar 52 (i.e. the area of blank 50) is approximately 2.1 square inches. Thus, throughout the entire machining operation the cross-sectional area of club head blank 50 is reduced by only approximately 25%. Club heads of different configurations can similarly be produced using side profile near-net-shape extrusions in which the machining operations remove only 15% to 30% of the profile area of the original extrusion. Indeed, the machining operations are so efficient that the finished parts still weigh between 30% and 45% of the weight of the original blank. This compares extremely favorably to billet machining in which the finished part often weighs only 10% to 20% of the weight of original billet. As used herein, near-net-shape means that the extrusion from which the club head blank is severed is no more than 150% larger in cross-section than the corresponding vertical profile (side or front) of the finished part, as opposed to machining of a billet or other wrought material typically provided in regular cross section shapes (e.g. square, round, rectangle). In many cases, however, as demonstrated above, the cross sectional area of the extrusion is only 100% larger or, in the case of the second embodiment, only 17% to 43% larger than the vertical profile area of the finished part (the finished part having a vertical profile area 70% to 85% of the area of the extrusion).

As can be seen from the foregoing use of a near-net-shape extrusion to form the blank from which the golf club head is machined allows for a very highly efficient machining operation with less wasted machining time, less wasted material and therefore substantial cost savings over the prior art methods of manufacturing golf club heads.

Although certain illustrative embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention shall be limited only to the extent required by the appended claims and the rules and principals of applicable law. 

1. A method of manufacturing a golf club head having a face adapted for striking a golf ball and a body extending rearward from the face, the method comprising: extruding a solid material to form an elongate bar having a longitudinal axis and an irregular cross section normal to the longitudinal axis, said irregular cross section being near-net-shape to a final profile of said golf club head; forming a club head blank by severing a portion of said elongate bar along a plane transverse to the longitudinal axis of the elongate bar; forming a datum in said club head blank; attaching said club head blank to a machining fixture using said datum as a reference point; and machining said club head blank to form a completed golf club head, wherein at least a portion of the face and the body of said golf club head are formed from a single club head blank.
 2. The method of claim 1, wherein: the irregular cross section has a near-net-shape to a front profile of said golf club head.
 3. The method of claim 2, wherein: the front profile of said golf club head has a predetermined area projected onto a vertical plane parallel to a horizontal line tangent to the face; and the irregular cross section of the elongate bar has an area that is no more than 100 percent greater than the predetermined area of the front profile.
 4. The method of claim 2, wherein: the front profile of said golf club head has a predetermined area projected onto a vertical plane parallel to a horizontal line tangent to the face; and the irregular cross section of the elongate bar has an area that is no more than 70 percent greater than the predetermined area of the front profile.
 5. The method of claim 1, wherein: the irregular cross section has a near-net-shape to a side profile of said golf club head.
 6. The method of claim 5, wherein: the side profile of said golf club head has a predetermined area projected onto a vertical plane normal to the face; and the irregular cross section of the elongate bar has an area that is no more than 50 percent greater than the predetermined area of the side profile.
 7. The method of claim 5, wherein: the side profile of said golf club head has a predetermined area projected onto a vertical plane normal to the face; and the irregular cross section of the elongate bar has an area that is no more than 35 percent greater than the predetermined area of the side profile.
 8. The method of claim 1, wherein: said golf club head further comprises a hose1 shank and at least a portion of the body and hose1 shank of said golf club head are formed from a single club head blank.
 9. The method of claim 1, wherein: the solid material comprises a metal.
 10. The method of claim 9, wherein: the metal comprises an aluminum alloy.
 11. A method of manufacturing a golf club head having a main body and a hose1 shank, said golf club having a front profile and a side profile, the method comprising: extruding a solid material to form an elongate bar having a longitudinal axis and an irregular cross section normal to the longitudinal axis, said irregular cross section being near-net-shape to the front profile of said golf club; forming a club head blank by severing a portion of said elongate bar; forming a datum in said club head blank; attaching said club head blank to a machining fixture using said datum as a reference point; and machining said club head blank to form a completed golf club head, wherein at least a portion of the face and the body of said golf club head are formed from a single club head blank.
 12. The method of claim 11, wherein: at least a portion of the body and hose1 shank of said golf club head are formed from a single club head blank.
 13. A golf club comprising: a machined face adapted for impacting a golf ball; a machined body extending rearward from said machined face, said machined face and machined body formed together by machining a single club head blank, the club head blank being formed by severing a portion of an elongate bar of extruded solid material having a longitudinal axis and an irregular cross section along a plane transverse to the longitudinal axis, the irregular cross section of the elongate bar having a near-net-shape to a vertical profile of said golf club head.
 14. The golf club of claim 13, wherein: the vertical profile of said golf club head comprises a front profile; and the irregular cross section of the elongate bar has an area that is no more than 100 percent larger than the area of the front profile of the golf club head.
 15. The golf club of claim 13, wherein: the vertical profile of said golf club head comprises a side profile; and the irregular cross section of the elongate bar has an area that is no more than 50 percent larger than the area of the side profile of the golf club head. 